package demo1;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class LeetCode30 {
    public List<Integer> findSubstring(String s, String[] words) {
        List<Integer> list = new ArrayList<>();
        Map<String, Integer> hash1 = new HashMap<>();
        for(String str : words) hash1.put(str, hash1.getOrDefault(str, 0) + 1);
        char[] arr = s.toCharArray();
        int len = words[0].length();
        int nw = words.length, n = arr.length;
        for(int i = 0; i < len; i++) {
            Map<String, Integer> hash2 = new HashMap<>();
            for(int left = i, right = i, count = 0; right + len <= n; right += len) {
                String in = s.substring(right, right + len);
                hash2.put(in, hash2.getOrDefault(in, 0) + 1);
                if(hash2.get(in) <= hash1.getOrDefault(in, 0)) count++;
                if(right - left + 1 > len * nw) {
                    String out = s.substring(left, left + len);
                    if(hash2.get(out) <= hash1.getOrDefault(out, 0)) count--;
                    hash2.put(out, hash2.get(out) - 1);
                    left += len;
                }
                if(count == nw) list.add(left);
            }
        }
        return list;
    }
}
